title: Serodiagnosis of dengue infection using rapid immunochromatography test in patients with probable dengue infection.
abstract: OBJECTIVE
  To determine the frequency of seropositive dengue infection using rapid immunochromatographic assay in patients with probable dengue infection as per WHO criteria.
  
  
  METHODS
  A cross-sectional observational study was conducted at Abbasi Shaheed Hospital, Karachi from July 2008 to January 2009. Patients presenting with acute febrile illness, rashes, bleeding tendencies, leucopenia and or thrombocytopenia were evaluated according to WHO criteria for probable dengue infection. Acute phase sera were collected after 5 days of the onset of fever as per WHO criteria. Serology was performed using rapid immunochromatographic (ICT) assay with differential detection of IgM and IgG. A primary dengue infection was defined by a positive IgM band and a negative IgG band whereas secondary infection was defined by a positive IgG band with or without positive IgM band.
  
  
  RESULTS
  Among 599 patients who met the WHO criteria for dengue infection, 251(41.9%) were found to be ICT reactive among whom 42 (16.73%) had primary infection. Secondary infection was reported in 209 (83.26%). Acute phase sera of 348 (58.09%) were ICT non reactive. Four patients died because of dengue shock syndrome among which three had secondary infection.
  
  
  CONCLUSIONS
  Early identification of secondary infection in acute phase sera using rapid ICT is valuable in terms of disease progression and mortality. However in highly suspected cases of dengue infection clinical management should not rely on negative serological results.
authors.affiliation: Medical Unit-III, Department of Medicine Abbasi Shaheed Hospital, Nazimabad, Karachi.
authors.forename: Aneela Altaf
authors.initials: AA
authors.lastname: Kidwai
authors.forename: Qaiser
authors.initials: Q
authors.lastname: Jamal
authors.lastname: Saher
authors.lastname: Mehrunnisa
authors.forename: Faiz-ur-rehman
authors.initials: FU
authors.lastname: Farooqi
authors.lastname: Saleem-Ullah
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood*; D002845:Chromatography / Q000379:methods*; D003430:Cross-Sectional Studies; D003715:Dengue / Q000175:diagnosis* / Q000276:immunology / Q000821:virology; D003716:Dengue Virus / Q000276:immunology* / Q000302:isolation & purification; D005260:Female; D006761:Hospitals; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D010154:Pakistan; D010343:Patient Admission / Q000706:statistics & numerical data; D012698:Serologic Tests / Q000379:methods*; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M